Rationale: Progress has been made in understanding how the cystic
fibrosis (CF) basic defect produces lung infection susceptibility. However, it
remains unclear why CF exclusively leads to chronic infections that are noninvasive
and highly resistant to eradication. Although biofilm formation has been suggested as
a mechanism, recent work raises questions about the role of biofilms in CF.
Objectives: To learn how airway conditions attributed to CF
transmembrane regulator dysfunction could lead to chronic infection, and to determine
if biofilm-inhibiting genetic adaptations that are common in CF isolates affect the
capacity of Pseudomonas aeruginosa to develop chronic infection
Methods: We studied P. aeruginosa isolates grown in
agar and mucus gels containing sputum from patients with CF and measured their
susceptibility to killing by antibiotics and host defenses. We also measured the
invasive virulence of P. aeruginosa grown in sputum gels using
airway epithelial cells and a murine infection model.
Measurements and Main Results: We found that conditions likely to result
from increased mucus density, hyperinflammation, and defective bacterial killing
could all cause P. aeruginosa to grow in bacterial aggregates.
Aggregated growth markedly increased the resistance of bacteria to killing by host
defenses and antibiotics, and reduced their invasiveness. In addition, we found that
biofilm-inhibiting mutations do not impede aggregate formation in gel growth
Conclusions: Our findings suggest that conditions associated with
several CF pathogenesis hypotheses could cause the noninvasive and resistant
infection phenotype, independently of the bacterial functions needed for biofilm
cystic fibrosis; chronic infection; Pseudomonas aeruginosa; biofilm
Intradural lumbar disc herniation (ILDH) is uncommon pathology. In present report, authors present a case of ILDH associated with dorsal herniation of the cauda equina rootlets in a 30-year-old male laborer who had chronic backache since last two years. To the best of our knowledge we are reporting this for first time. Report demonstrates the natural course of ILDH.
Intradural disc herniation; Duroplasty; Herniated cauda equina rootlets
Trauma is the leading nonobstetric cause of maternal death. The worst complication can be fetal compromise that threatens premature labor or even fetal death. We are reporting a case of a 30-year-old primi, short stature woman who had fracture femur with hypovolaemic shock. Managing such trauma complicated by shock in a pregnant patient needs multidisciplinary approach. Clinician team evaluating and coordinating the care of pregnant trauma patient should understand the pathophysiological changes in pregnancy with trauma to manage hypovolaemic shock, related complications, treatment of fracture, and radiation exposure to the fetus. The use of imaging studies, invasive hemodynamics and surgery, if necessary, should be individualized. A clear understanding of fetal viability, physiological changes of pregnancy, and pathophysiology of shock, is mandatory for optimal, maternal functional, and obstetrical outcome.
Fracture femur; ionizing; pregnancy; radiation; trauma
To evaluate the usefulness of conventional spinal surgery as palliative procedure to rehabilitate dorsolumbar injuries in a rural setup.
Materials and Methods:
Twenty-three patients with dorsolumbar spine injury with complete paraplegia were assessed on the clinical and social rehabilitation parameters after surgical stabilization at Acharya Vinoba Bhave Rural Hospital Sawangi, Wardha, India. The study group comprised 21 male and 2 female patients. The dorsolumbar spine injury was fixed by conventional posterior instrumentation using short-segment pedicle screw system and Harrington rod system with or without fusion. Functional and neurologic outcome was recorded in the follow-up period by using Functional Independence Measure and Frankel grade, respectively. Correlation and analysis of results was established statistically.
Functional outcome showed statistically significant improvement. Social cognition was found intact in a significant number of patients.
This study demonstrates the usefulness of conventional instrumentation as palliative surgical approach to stabilize and rehabilitate patients from deprived sector of rural India.
Conventional spinal instrumentation; Palliative care; Rehabilitation; Rural setup; Total traumatic paraplegia
A novel antiinfective approach is to exploit stresses already imposed on invading organisms by the in vivo environment. Fe metabolism is a key vulnerability of infecting bacteria because organisms require Fe for growth, and it is critical in the pathogenesis of infections. Furthermore, humans have evolved potent Fe-withholding mechanisms that can block acute infection, prevent biofilm formation leading to chronic infection, and starve bacteria that succeed in infecting the host. Here we investigate a “Trojan horse” strategy that uses the transition metal gallium to disrupt bacterial Fe metabolism and exploit the Fe stress of in vivo environments. Due to its chemical similarity to Fe, Ga can substitute for Fe in many biologic systems and inhibit Fe-dependent processes. We found that Ga inhibits Pseudomonas aeruginosa growth and biofilm formation and kills planktonic and biofilm bacteria in vitro. Ga works in part by decreasing bacterial Fe uptake and by interfering with Fe signaling by the transcriptional regulator pvdS. We also show that Ga is effective in 2 murine lung infection models. These data, along with the fact that Ga is FDA approved (for i.v. administration) and there is the dearth of new antibiotics in development, make Ga a potentially promising new therapeutic for P. aeruginosa infections.
Biofilm cells are less susceptible to antimicrobials than their planktonic counterparts. While this phenomenon is multifactorial, the ability of the biofilm matrix to reduce antibiotic penetration into the biofilm is thought to be of limited importance, as previous studies suggest that antibiotics move fairly rapidly through biofilms. In this study, we monitored the transport of two clinically relevant antibiotics, tobramycin and ciprofloxacin, into non-mucoid P. aeruginosa biofilms. To our surprise, we showed that the positively charged antibiotic tobramycin is sequestered to the biofilm periphery, while the neutral antibiotic ciprofloxacin readily penetrated. We provide evidence that tobramycin in the biofilm periphery both stimulated a localized stress response and killed bacteria in these regions, but not in the underlying biofilm. Although it is unclear which matrix component binds tobramycin, its penetration was increased by the addition of cations in a dose-dependent manner, which led to increased biofilm death. These data suggest that ionic interactions of tobramycin with the biofilm matrix limit its penetration. We propose that tobramycin sequestration at the biofilm periphery is an important mechanism in protecting metabolically active cells that lie just below the zone of sequestration.
Shrinking lung syndrome (SLS) is a infrequently reported manifestation of systemic lupus erythematosus (SLE). Reported prevalence of SLS is about 0.5% in SLE patients. Pathogenesis is not fully understood and different therapeutic modalities have been employed with variable results, as only 77 cases of SLS have been documented in literature. SLS in SLE-Scleroderma overlap has not been reported yet. We report a patient of SLE - scleroderma overlap presenting with dyspnea, intermittent orthopnea and pleuritic chest pain. Evaluation revealed elevated hemidiaphragms and severe restrictive defect. She was eventually diagnosed as a case of SLS. This case report is a reminder to the medical fraternity that SLS although a rare complication must be thought of in the special subset of patients of SLE having respiratory symptoms.
Scleroderma; scleroderma shrinking lung syndrome; systemic lupus erythematosus
Bacteria become highly tolerant to antibiotics when nutrients are limited. The inactivity of antibiotic targets caused by starvation-induced growth arrest is thought to be a key mechanism producing tolerance (1). Here we show that the antibiotic tolerance of nutrient-limited and biofilm Pseudomonas aeruginosa is mediated by active responses to starvation, rather than by the passive effects of growth arrest. The protective mechanism is controlled by the starvation-signaling stringent response (SR), and our experiments link SR–mediated tolerance to reduced levels of oxidant stress in bacterial cells. Furthermore, inactivating this protective mechanism sensitized biofilms by several orders of magnitude to four different classes of antibiotics, and markedly enhanced the efficacy of antibiotic treatment in experimental infections.
Prospective study conducted at Jawaharlal Nehru Medical College, Datta Meghe Institute of Medical Sciences, Wardha, India.
To show the efficacy of decompression in the late presentation of cervical spinal cord disorders.
Overview of Literature
Studies by various authors have shown that early spinal decompression results in better neurological outcomes.
From January 2003 to January 2005, 11 of the 41 patients with cervical spinal cord compression, meeting the inclusion criteria, underwent anterior decompression; interbody graft placement and stabilization by anterior cervical locking plate. The neurologic and functional outcomes were recorded.
Five patients had spinal cord injury and 6 patients had compressive cervical myelopathy. Complications included 1 death and 1 plate loosening. No patient lost their preoperative neurological status. One patient had no improvement, 2 patients showed full recovery. The mean follow-up is 28.3 month. At the of rehabilitation, 6 were able to walk without support), 2 could walk with support, and 1 needed a wheelchair. The average American Spinal Injury Association motor score on admission to the hospital, 32.8 (standard deviation [SD], 30.5); admission to rehabilitation, 38.6 (SD, 32.4); discharge from rehabilitation, 46.2 (SD, 33.7). The most recent follow-up was 64.0 (SD, 35.3).
The anterior approach for cervical decompression allows for adequate decompression. This decompression is the best chance offered in even late reported cases, including posttraumatic cases where there is no evidence of cord transactions. The use of anterior cervical plates reduces the chances of graft loosening, extruding, or collapsing.
Cervical vertebrae; Neglected disease; Quadriparesis; Surgical decompression
In human beings, Parkinson’s disease (PD) is associated
with the oligomerization and amyloid formation of α-synuclein
(α-Syn). The polyphenolic Asian food ingredient curcumin has
proven to be effective against a wide range of human diseases including
cancers and neurological disorders. While curcumin has been shown
to significantly reduce cell toxicity of α-Syn aggregates, its
mechanism of action remains unexplored. Here, using a series of biophysical
techniques, we demonstrate that curcumin reduces toxicity by binding
to preformed oligomers and fibrils and altering their hydrophobic
surface exposure. Further, our fluorescence and two-dimensional nuclear
magnetic resonance (2D-NMR) data indicate that curcumin does not bind
to monomeric α-Syn but binds specifically to oligomeric intermediates.
The degree of curcumin binding correlates with the extent of α-Syn
oligomerization, suggesting that the ordered structure of protein
is required for effective curcumin binding. The acceleration of aggregation
by curcumin may decrease the population of toxic oligomeric intermediates
of α-Syn. Collectively; our results suggest that curcumin and
related polyphenolic compounds can be pursued as candidate drug targets
for treatment of PD and other neurological diseases.
Curcumin; α-synuclein; amyloid; oligomers; toxicity; Parkinson’s disease
Bacterial biofilm has been shown to play a role in delaying wound healing of chronic wounds, a major medical problem that results in significant healthcare burden. A reproducible animal model could be very valuable for studying the mechanism and management of chronic wounds. Our previous work demonstrated that Pseudomonas aeruginosa (PAO1) biofilmchallenge on wounds in diabetic (db/db) mice significantly delayed wound healing. In this wound time course study, we further characterize the bacterial burden, delayed wound healing and certain aspects of the host inflammatory response in the PAO1 biofilm-challenged db/db mouse model. PAO1 biofilms were transferred onto 2 day old wounds created on the dorsal surface of db/db mice. Control wounds without biofilm-challenge healed by 4 weeks, consistent with previous studies; none of the biofilm-challenged wounds healed by 4 weeks; 64% of the biofilm-challenged wounds healed by 6 weeks; and all of the biofilm-challenged wounds healed by 8 weeks. During the wound healing process, P. aeruginosa were gradually cleared from the wounds while the presence of S. aureus (part of the normal mouse skin flora) increased. Scabs from all unhealed wounds contained 107
P. aeruginosa, which was 100 fold higher than the counts isolated from wound beds (i.e. 99% of the P. aeruginosa was in the scab). Histology and genetic analysis showed proliferative epidermis, deficient vascularization and increased inflammatory cytokines. Hypoxia inducible factor (HIF) expression increased 3 fold in 4 week wounds. In summary, our study demonstrates that biofilm-challenged wounds typically heal in approximately 6 weeks, at least 2 weeks longer than non biofilm-challenged normal wounds. These data suggest that this delayed wound healing model enables the in vivo study of bacterial biofilm responses to host defenses and the effects of biofilms on host wound healing pathways. It may also be used to test anti-biofilm strategies the treatment of chronic wounds.
Pseudomonas aeruginosa; biofilm; wound infection; keratinocytes; inflammatory response; gene expression
Since the 1989 discovery that mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene cause cystic fibrosis (CF), there has been substantial progress toward understanding the molecular basis for CF lung disease, leading to the discovery and development of new therapeutic approaches. However, the earliest impact of the loss of CFTR function on airway physiology and structure and its relationship to initial infection and inflammation are poorly understood. Universal newborn screening for CF in the United States represents an unprecedented opportunity for investigating CF clinical manifestations very early in life. Recently developed animal models with pulmonary phenotypic manifestations also provide a window into the early consequences of this genetic disorder. For these reasons, the National Heart, Lung, and Blood Institute (NHLBI) convened a working group of extramural experts, entitled “Future Research Directions in Early CF Lung Disease” on September 21–22, 2010, to identify future research directions of great promise in CF. The priority areas identified included (1) exploring pathogenic mechanisms of early CF lung disease; (2) leveraging newborn screening to elucidate the natural history of early lung disease; (3) developing a spectrum of biomarkers of early lung disease that reflects CF pathophysiology, clinical outcome, and response to treatment; (4) exploring the role of genetics/genomics (e.g., modifier genes, gene–environmental interactions, and epigenetics) in early CF pathogenesis; (5) defining early microbiological events in CF lung disease; and (6) elucidating the initial airway inflammatory, remodeling, and repair mechanisms in CF lung disease.
cystic fibrosis; airway disease; innate immunity; microbiology; genetics
Peptide/protein hormones could be stored as non-toxic amyloid-like structures in pituitary secretory granules. ACTH and β-endorphin are two of the important peptide hormones that get co-stored in the pituitary secretory granules. Here, we study molecular interactions between ACTH and β-endorphin and their colocalization in the form of amyloid aggregates. Although ACTH is known to be a part of ACTH-β-endorphin aggregate, ACTH alone cannot aggregate into amyloid under various plausible conditions. Using all atom molecular dynamics simulation we investigate the early molecular interaction events in the ACTH-β-endorphin system, β-endorphin-only system and ACTH-only system. We find that β-endorphin and ACTH formed an interacting unit, whereas negligible interactions were observed between ACTH molecules in ACTH-only system. Our data suggest that ACTH is not only involved in interaction with β-endorphin but also enhances the stability of mixed oligomers of the entire system.
Chronic wounds are a major clinical problem that leads to considerable morbidity and mortality. We hypothesized that an important factor in the failure of chronic wounds to heal was the presence of microbial biofilm resistant to antibiotics and protected from host defenses. A major difficulty in studying chronic wounds is the absence of suitable animal models. The goal of this study was to create a reproducible chronic wound model in diabetic mice by application of bacterial biofilm. Six millimeter punch biopsy wounds were created on the dorsal surface of diabetic (db/db) mice, subsequently challenged with Pseudomonas aeruginosa (PAO1) biofilms two days post-wounding, and covered with semi-occlusive dressings for two weeks. Most of the control wounds were epithelialized by 28 days post-wounding. In contrast, none of biofilm challenged wounds were closed. Histological analysis showed extensive inflammatory cell infiltration, tissue necrosis and epidermal hyperplasia adjacent to challenged wounds- all indicators of an inflammatory non-healing wound. Quantitative cultures and transmission electron microscopy demonstrated that the majority of bacteria were in the scab above the wound bed rather than in the wound tissue. The model was reproducible, allowed localized cutaneous wound infections without high mortality and demonstrated delayed wound healing following biofilm challenge. This model may provide an approach to study the role of microbial biofilms in chronic wounds as well as the effect of specific biofilm therapy on wound healing.
wound matrix; bacteria; scab; immunohistology; electron microscopy
Alzheimer's disease (AD) is the most common form of dementia that affects several million people worldwide. The major neuropathological hallmarks of AD are the presence of extracellular amyloid plaques that are composed of Aβ40 and Aβ42 and intracellular neurofibrillary tangles (NFT), which is composed of hyperphosphorylated protein Tau. While the amyloid plaques and NFT could define the disease progression involving neuronal loss and dysfunction, significant cognitive decline occurs before their appearance. Although significant advances in neuroimaging techniques provide the structure and physiology of brain of AD cases, the biomarker studies based on cerebrospinal fluid (CSF) and plasma represent the most direct and convenient means to study the disease progression. Biomarkers are useful in detecting the preclinical as well as symptomatic stages of AD. In this paper, we discuss the recent advancements of various biomarkers with particular emphasis on CSF biomarkers for monitoring the early development of AD before significant cognitive dysfunction.
The PLUNC (“Palate, lung, nasal epithelium clone”) protein is an abundant secretory product of epithelia present throughout the conducting airways of humans and other mammals, which is evolutionarily related to the lipid transfer/lipopolysaccharide binding protein (LT/LBP) family. Two members of this family - the bactericidal/permeability increasing protein (BPI) and the lipopolysaccharide binding protein (LBP) - are innate immune molecules with recognized roles in sensing and responding to Gram negative bacteria, leading many to propose that PLUNC may play a host defense role in the human airways.
Based on its marked hydrophobicity, we hypothesized that PLUNC may be an airway surfactant. We found that purified recombinant human PLUNC greatly enhanced the ability of aqueous solutions to spread on a hydrophobic surface. Furthermore, we discovered that PLUNC significantly reduced surface tension at the air-liquid interface in aqueous solutions, indicating novel and biologically relevant surfactant properties. Of note, surface tensions achieved by adding PLUNC to solutions are very similar to measurements of the surface tension in tracheobronchial secretions from humans and animal models. Because surfactants of microbial origin can disperse matrix-encased bacterial clusters known as biofilms , we hypothesized that PLUNC may also have anti-biofilm activity. We found that, at a physiologically relevant concentration, PLUNC inhibited biofilm formation by the airway pathogen Pseudomonas aeruginosa in an in vitro model.
Our data suggest that the PLUNC protein contributes to the surfactant properties of airway secretions, and that this activity may interfere with biofilm formation by an airway pathogen.
Many respiratory pathogens, including Hemophilus influenzae, Streptococcus pneumoniae, and Pseudomonas aeruginosa, express neuraminidases that can cleave α2,3-linked sialic acids from glycoconjugates. As mucosal surfaces are heavily sialylated, neuraminidases have been thought to modify epithelial cells by exposing potential bacterial receptors. However, in contrast to neuraminidase produced by the influenza virus, a role for bacterial neuraminidase in pathogenesis has not yet been clearly established. We constructed a mutant of P. aeruginosa PAO1 by deleting the PA2794 neuraminidase locus (Δ2794) and tested its virulence and immunostimulatory capabilities in a mouse model of infection. Although fully virulent when introduced i.p., the Δ2794 mutant was unable to establish respiratory infection by i.n. inoculation. The inability to colonize the respiratory tract correlated with diminished production of biofilm, as assessed by scanning electron microscopy and in vitro assays. The importance of neuraminidase in biofilm production was further demonstrated by showing that viral neuraminidase inhibitors in clinical use blocked P. aeruginosa biofilm production in vitro as well. The P. aeruginosa neuraminidase has a key role in the initial stages of pulmonary infection by targeting bacterial glycoconjugates and contributing to the formation of biofilm. Inhibiting bacterial neuraminidases could provide a novel mechanism to prevent bacterial pneumonia.
Pseudomonas aeruginosa can notably cause both acute and chronic infection. While several virulence factors are implicated in the acute phase of infection, advances in understanding bacterial pathogenesis suggest that chronic P. aeruginosa infection is related to biofilm formation. However, the relationship between these two forms of disease is not well understood. Accumulating evidence indicates that, during acute infection, P. aeruginosa enters epithelial cells, a process viewed as either a host-mediated defense response or a pathogenic mechanism to avoid host-mediated killing. We investigated the possibility that epithelial cell entry during early P. aeruginosa-epithelial cell contact favors bacterial survival and is linked to chronic infection. Using electron microscopy and confocal microscopy to analyze primary culture airway epithelial cells infected with P. aeruginosa, we found that epithelial cells developed pod-like clusters of intracellular bacteria with regional variation in protein expression. Extracellular gentamicin added to the medium after acute infection led to the persistence of intracellular P. aeruginosa for at least 3 days. Importantly, compared to bacterial culture under planktonic conditions, the intracellular bacteria were insensitive to growth inhibition or killing by antibiotics that were capable of intraepithelial cell penetration. These findings suggest that P. aeruginosa can use airway epithelial cells as a sanctuary for persistence and develop a reversible antibiotic resistance phenotype characteristic of biofilm physiology that can contribute to development of chronic infection.
The opportunistic human pathogen Pseudomonas aeruginosa causes persistent airway infections in patients with cystic fibrosis (CF). To establish these chronic infections, P. aeruginosa must grow and proliferate within the highly viscous sputum in the lungs of CF patients. In this study, we used Affymetrix GeneChip microarrays to investigate the physiology of P. aeruginosa grown using CF sputum as the sole source of carbon and energy. Our results indicate that CF sputum readily supports high-density P. aeruginosa growth. Furthermore, multiple signals, which reduce swimming motility and prematurely activate the Pseudomonas quinolone signal cell-to-cell signaling cascade in P. aeruginosa, are present in CF sputum. P. aeruginosa factors critical for lysis of the common CF lung inhabitant Staphylococcus aureus were also induced in CF sputum and increased the competitiveness of P. aeruginosa during polymicrobial growth in CF sputum.